package com.hth.zhushanmall.product.service.impl;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.hth.zhushanmall.product.service.CategoryBrandRelationService;
import com.hth.zhushanmall.product.vo.Catelog2Vo;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hth.common.utils.PageUtils;
import org.apache.commons.lang.StringUtils;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.cache.annotation.Caching;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;

import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.hth.common.utils.Query;

import com.hth.zhushanmall.product.dao.CategoryDao;
import com.hth.zhushanmall.product.entity.CategoryEntity;
import com.hth.zhushanmall.product.service.CategoryService;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.CollectionUtils;

import javax.annotation.Resource;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {

    //private Map<String,Object> cache = new HashMap<>();

    @Resource
    CategoryBrandRelationService categoryBrandRelationService;

    @Autowired
    StringRedisTemplate redisTemplate;

    @Autowired
    RedissonClient redisson;

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {
        //1.查出所有分类
        List<CategoryEntity> entities = baseMapper.selectList(null);

        //2.组装成父子的树形结构

        //2.1找到所有的一级分类
        List<CategoryEntity> levelMenus = entities.stream().filter(categoryEntity ->
                categoryEntity.getParentCid() == 0
        ).map((menu) -> {
            menu.setChildren(getChildrens(menu, entities));
            return menu;
        }).sorted((menu1, menu2) -> {
            return (menu1.getSort() == null ? 0 : menu1.getSort()) - (menu2.getSort() == null ? 0 : menu2.getSort());
        }).collect(Collectors.toList());

        return levelMenus;
    }

    @Override
    public void removeMenuByIds(List<Long> asList) {
        //TODO 1.检查当前删除的菜单，是否被别的地方应用

        //逻辑删除
        baseMapper.deleteBatchIds(asList);
    }

    @Override
    public Long[] findCatelogPath(Long catelogId) {
        List<Long> paths = new ArrayList<>();

        List<Long> parentPath = findParentPath(catelogId, paths);

        Collections.reverse(parentPath);

        return parentPath.toArray(new Long[parentPath.size()]);
    }

    /**
     * 级联更新所有的数据
     *  @CacheEvict:失效模式
     * @param category
     */
    //@CacheEvict(value = "category",key = "'getLevel1Categorys'")
    @CacheEvict(value = "category",allEntries = true)
    @Transactional
    @Override
    public void updateCascade(CategoryEntity category) {
        this.updateById(category);
        categoryBrandRelationService.updateCategory(category.getCatId(), category.getName());
    }

    @Cacheable(value = {"category"},key = "#root.method.name",sync = true)
    @Override
    public List<CategoryEntity> getLevel1Categorys() {
        List<CategoryEntity> categoryEntities = baseMapper.selectList(new QueryWrapper<CategoryEntity>().eq("parent_cid", 0));
        return categoryEntities;
    }

    @Cacheable(value = "category",key = "#root.methodName")
    @Override
    public Map<String, List<Catelog2Vo>> getCatelogJson() {
        List<CategoryEntity> selectList = baseMapper.selectList(null);
        //1.查询一级分类
        List<CategoryEntity> level1Category = getParent_cid(selectList, 0L);
        //2.封装数据
        Map<String, List<Catelog2Vo>> parent_cid = level1Category.stream().collect(Collectors.toMap(k -> k.getCatId().toString(), v -> {
            //1)查询每个一级分类的二级分类
            List<CategoryEntity> categoryEntities = getParent_cid(selectList, v.getCatId());
            //2)封装上面的结果
            List<Catelog2Vo> catelog2Vos = null;
            if (categoryEntities != null) {
                catelog2Vos = categoryEntities.stream().map(l2 -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(), null, l2.getCatId().toString(), l2.getName());
                    //2.1)把当前二级分类和三级分类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(selectList, l2.getCatId());
                    if (level3Catelog != null) {
                        //封装成指定格式
                        List<Catelog2Vo.Catelog3Vo> collect = level3Catelog.stream().map(l3 -> {
                            Catelog2Vo.Catelog3Vo catelog3Vo = new Catelog2Vo.Catelog3Vo(l2.getCatId().toString(), l3.getCatId().toString(), l3.getName());
                            return catelog3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatelog3List(collect);
                    }
                    return catelog2Vo;
                }).collect(Collectors.toList());
            }
            return catelog2Vos;
        }));
        return parent_cid;
    }

    //TODO 产生堆外内存溢出：OutOfDirectMemoryError

    /**
     * 1.空结果缓存：解决缓存穿透
     * 2.设置过期时间（加随机值），解决缓存雪崩
     * 3.加锁：解决缓存击穿
     */

    //@Override
    public Map<String, List<Catelog2Vo>> getCatelogJson2() {
        //给缓存中放json字符串，拿到的json字符串，还用逆转为能用的对象类型：【序列化与反序列化】

        //加入缓存逻辑，缓存中存的数据是json字符串
        //JSON跨语言，跨平台兼容
        String catalogJSON = redisTemplate.opsForValue().get("catalogJSON");
        if (StringUtils.isEmpty(catalogJSON)) {
            System.out.println("缓存不命中....将要查询数据库...");
            //缓存中没有，查询数据库
            Map<String, List<Catelog2Vo>> catalogJsonFromDb = getCatelogJsonFromDbWithRedisLock();

            return catalogJsonFromDb;
        }
        System.out.println("缓存命中....直接返回...");
        //转为我们指定的对象
        Map<String, List<Catelog2Vo>> result = JSON.parseObject(catalogJSON, new TypeReference<Map<String, List<Catelog2Vo>>>() {
        });
        return result;
    }

    public Map<String, List<Catelog2Vo>> getCatelogJsonFromDbWithRedissonLock() {

        //占分布式锁.去redis占坑
        RLock lock = redisson.getLock("catalogJson-lock");
        lock.lock();

        Map<String, List<Catelog2Vo>> dataFromDb;
        try {
            dataFromDb = getDataFromDb();

        }finally {
            lock.unlock();
        }

        return dataFromDb;

    }

    public Map<String, List<Catelog2Vo>> getCatelogJsonFromDbWithRedisLock() {

        //占分布式锁.去redis占坑
        String uuid = UUID.randomUUID().toString();
        Boolean lock = redisTemplate.opsForValue().setIfAbsent("lock",uuid,300,TimeUnit.SECONDS);
        if (lock){
            System.out.println("获取分布式锁成功.....");
            //加锁成功...执行业务
            //设置过期时间
            //redisTemplate.expire("lock",30,TimeUnit.SECONDS);
            Map<String, List<Catelog2Vo>> dataFromDb;
            try {
                dataFromDb = getDataFromDb();

            }finally {
                String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
                //删除锁
                redisTemplate.execute(new DefaultRedisScript<Long>(script, Long.class), Collections.singletonList("lock"), uuid);
            }
            //获取值对比+对比成功删除=原子操作 lua脚本解锁
            /*String lockValue = redisTemplate.opsForValue().get("lock");
            if (uuid.equals(lockValue)){
                //删除我自己的锁
                redisTemplate.delete("lock");
            }*/


            return dataFromDb;
        }else {
            //加锁失败....重试
            //休眠100ms重试
            System.out.println("获取分布式锁失败.....等待重试");
            try {
                Thread.sleep(200);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return getCatelogJsonFromDbWithRedisLock();//自旋的方式
        }

    }

    private Map<String, List<Catelog2Vo>> getDataFromDb() {
        String catalogJSON = redisTemplate.opsForValue().get("catalogJSON");
        if (!StringUtils.isEmpty(catalogJSON)) {
            //缓存不为空直接返回
            Map<String, List<Catelog2Vo>> result = JSON.parseObject(catalogJSON, new TypeReference<Map<String, List<Catelog2Vo>>>() {
            });
            return result;
        }

        List<CategoryEntity> selectList = baseMapper.selectList(null);

        List<CategoryEntity> level1Categorys = getParent_cid(selectList, 0L);

        //2.封装数据
        Map<String, List<Catelog2Vo>> parent_Cid = level1Categorys.stream().collect(Collectors.toMap(k -> k.getCatId().toString(), v -> {
            //每一个的一级分类，查到这个一级分类的二级分类
            List<CategoryEntity> categoryEntities = getParent_cid(selectList, v.getCatId());
            //封装上面的结果
            List<Catelog2Vo> catelog2Vos = null;

            if (categoryEntities != null) {

                catelog2Vos = categoryEntities.stream().map(l2 -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(), null, l2.getCatId().toString(), l2.getName());
                    //找当前二级分类的三级分类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(selectList, l2.getCatId());
                    if (level3Catelog != null) {
                        List<Catelog2Vo.Catelog3Vo> collect = level3Catelog.stream().map(l3 -> {

                            //封装成指定格式
                            Catelog2Vo.Catelog3Vo catelog3Vo = new Catelog2Vo.Catelog3Vo(l2.getCatId().toString(), l3.getCatId().toString(), l3.getName());

                            return catelog3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatelog3List(collect);
                    }

                    return catelog2Vo;
                }).collect(Collectors.toList());
            }

            return catelog2Vos;
        }));

        //查到的数据再放入缓存，将对象转为json放在缓存中
        String s = JSON.toJSONString(parent_Cid);
        redisTemplate.opsForValue().set("catalogJSON", s, 1, TimeUnit.DAYS);
        return parent_Cid;
    }

    //从数据库查询并封装分类数据
    public Map<String, List<Catelog2Vo>> getCatelogJsonFromDbWithLocalLock() {

        //如果缓存中有就用缓存的
        /*Map<String, List<Catelog2Vo>> catalogJson = (Map<String, List<Catelog2Vo>>) cache.get("catalogJson");
        if (cache.get("catalogJson") == null){
            //调用业务,返回数据有放入缓存
            cache.put("catalogJson",parent_Cid);
        }
        return catalogJson;*/

        synchronized (this) {
            //得到锁以后，我们再去缓存中确定一次，如果没有才需要继续查询
            return getDataFromDb();
        }


    }

    private List<CategoryEntity> getParent_cid(List<CategoryEntity> selectList, Long parent_cid) {
        List<CategoryEntity> collect = selectList.stream().filter(item -> item.getParentCid().equals( parent_cid)).collect(Collectors.toList());
        //return baseMapper.selectList(new QueryWrapper<CategoryEntity>().eq("parent_cid", selectList.getCatId()));
        return collect;
    }

    private List<Long> findParentPath(Long catelogId, List<Long> paths) {
        //1.收集当前节点id
        paths.add(catelogId);
        CategoryEntity byId = this.getById(catelogId);
        if (byId.getParentCid() != 0) {
            findParentPath(byId.getParentCid(), paths);
        }
        return paths;
    }

    //递归查找所有菜单的子菜单
    private List<CategoryEntity> getChildrens(CategoryEntity root, List<CategoryEntity> all) {

        List<CategoryEntity> children = all.stream().filter(categoryEntity -> {
            return categoryEntity.getParentCid() == root.getCatId();
        }).map(categoryEntity -> {
            //1.找到子菜单
            categoryEntity.setChildren(getChildrens(categoryEntity, all));
            return categoryEntity;
        }).sorted((menu1, menu2) -> {
            //2.菜单的排序
            return (menu1.getSort() == null ? 0 : menu1.getSort()) - (menu2.getSort() == null ? 0 : menu2.getSort());
        }).collect(Collectors.toList());

        return children;
    }


}